Gyro erection system



March 18, 1952 R, R, SELIGER 2,589,874

GYRO ERECTION SYSTEM Filed June 30, 1949 2 Sl'lEETS-Sl-IEET l IN VEN TOR.

RUDOLF R. SEL/GER March 18, 1952 R, R. sl-:LIGER GYRo ERECTION SYSTEM :md June so, 1949 2 SHEETS-SHEET 2 IN VEN TOR.

RUDOLF R. SEL /GE/Q azz/k Mamme/Vg Patented Mar. 18, 1952 GYRO ERECTION SYSTEM Rudolf It. Seliger, Palisades Park, N. J., assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application June 30, 1949, Serial No. 102,389

12 Claims. (Cl. i4- 5.47)

The present invention relates generally to gyrol scopes and more particularly to a novel erection system therefor. i

`A non-pendulous vertical gyroscope when1deenergized will automatically come to rest with its spin axis in some position other than that assumed when the gyroscope is operating normally.

If the gyroscope is energized while in such a rest position, the spin axis will revolve about the true vertical, tracing a cone in space and gradually precessinto-the desired vertical position. It'may take a considerable 'time before the spin axis attains the latter position. It is often inconvenient and in certain applications impossible to wait ,until the gyro reaches the desired operating position. If control equipment such as an aircraft automatic pilot, for example, should accidentally be energized while the gyro is precessing into its normal operating position it is possible to, seriously impair the ei'ectiveness of the automatic pilot.

It is, therefore, desirable to bring the "gyro spin axis to true verticalv before energizing the gyro 'and to prevent its connection to the control is to provide novel, simple and effective means` for bringing the spin axis of a gyroscope into a desired reference position and thereafter applying power to thegyro to maintain the spin axis inthe reference position. j Y 1.

Another object of the invention is vto provide novel means for automaticallybringing the spin axis vcfa gyroscope into a' desired reference position.

Another object is to provide novel control means whereby the pitch and the bank axes of- Aa vertical gyroscope are automaticallyoriented with respect to the true vertical prior to the application of power to the gyro rotor. j: y

A further object is to provide novel erection matically bring the spin axis of the gyro to a true vertical position prior to the application of power to the .gyro rotor togetherwith means for dis- 2 connecting the erection means during a coordi nated turn of the craft on which the gyro is mounted.

Another object is to provide novel gyro control means including a time delay relay whereby pitch and bankrerection torque motors of an erection system are utilized to bring the spin axis of a vertical gyroscope into true vertical, prior to th application of power to the gyroscope. n I 1- Still another object of the invention isyto provide a' novel gyro erection system whereby-the pitch and bank erection torque motors are utilized to center the gyroscope in the'bank and pitch axis, respectively, and following a predetermined `time interval energize the gyroscope and automatically connect said pitch and bank torque motors, respectively, for normal erecting operation.

These and other objects and ladvantages of the invention will appear more fully hereinafter from a consideration of the'detailed description which follows, taken together with the accompanying drawings wherein one embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention.

In the drawingswherein like reference characters `referto like parts in both views: Fig. lis a perspective pictorial representation showing the relationship between the gyro and the various 'control units associated therewith..

Fig. 2 is a schematic wiring diagram of one embodiment of the novel erecting means according to thepresent invention;

For a better understanding of the present invention reference is had to Fig. 1 wherein a gyro .vertical is illustrated comprising a rotor bearing n `I8 being mutually perpendicular to eachother f means for a vertical gyroscope which will auto-1355 and to the spin axis. The supporting memberv I6 is xed with respect to the craft o'n which the gyro is mounted.

The gyro may be mounted on a craft whose ldirection of flight is represented in the direction of the arrow so that the gyro axisdened by trunnions i8, may be termed thebank axis, and

the axis deined by trunnions I4 may be termed @the pitchaxisv'Fixed to the extreme ends of 50 coupled tdlpendulum 36.

l 94 and 36.

ground potential through cathode resistances' |86 trunnions I4 are the rotor elements of an inductive pick-od device 28 and an erection motor 22.l The statorwindings of the pick-01T device and the motor are mounted on gimbal ring |2. The rotor elements of pick-off device 24 and erection motor 26 are similarly mounted on the extremities of the trunnions I8 and the stator elements thereof are mounted on the supporting member v Also mounted on the supporting member are a pair of pendulous pick-oil devices 28 and 30j.

whose rotor elements are journalled parallel to the pitch and bank axis, respectively. 'A pendulous mass 32 is clamped to the rotor shaft34 of pick-olf device 28 and a similar pendulousv mass 36 is clamped to rotor shaft 38 of pick-oli dev-ice 3B so as to maintain the rotors stationary with respect to the vertical by the gravitational force exerted on the pendulous masses about .their respective axes.

'prisingfa stationary stator winding-48 mounted on the supporting member l and a rotor winding Rotor winding 58 is connected in series with rotor winding 52 of pick-foil` device 24 whose stator winding 54 is also mounted on the supporting member I6.

rIlhe combined output of rotor windings 42V and 44 is connected to control grid 543 of amplifier Atube 58 and the combined output of rotor windingsil and 52 is connected to control gridf64. of

amplifier tube @S through normally closedfcontacts 6D of a switch S2.

The output of tube 58 is connected to control grid 10 of amplifier 12 whose output in turn is The output Aof amplier source of D. C. power. .A Ydetailed description .of the .ampliers per se is not ,deemed necessary as such amplifiers are wellknown in .the art.

A conventional multi-vibrator generally indi--4 cated 4by numeral 'S2' is lshown as comprising `aV pair of triode tubes`94 and 96 whose plates are.' connected to the common source of. D. C.y power.' through apair; ofvplate. resistancesv 93 and '108;'

respectively. Gridleakresistances |82 and |04 are connected to the respective cathodes of tubes The cathodes are connected to arid'l, respectively. The plate of tube '7.94 is connected to the control 'grid of tube 93 through .a coupling capacitorHZ and the plate of.tube 9.6 jis'. connected tothe control grid of tube 94 through a coupling capacitor H8. The capacitors are of the variable type and 'ganged together so that by increasing the capacitance of one of As is relative capacitance of the coupling capacitors.

ytube there will oe no potential The frequency of the multi-vibrator is of course dependent upon the time constant of the respective capacitor-grid leak resistance values. By gauging the capacitors as shown, the frequency of the Vmulti-vibrator may be kept constant while varying the on-off conducting periods of thetubes. With no current flowing through the drop across the corresponding cathode resistor. However, when the tube is conducting, a current will flow through the cathode resistor and a voltage proportional to the current will be developed across the resistor, the cathode becoming positive with urespect to ground. This voltage will be in the 'form of a pulse or nearly square wave shape.

The pulse appearing across cathode resistor |06 is used' to control the gain of ampliiiers 58 and 66, and for this purpose the grid leak resistors ||4 and H8 of ampliiiers 58 and 68, respectively, are connected to the cathode of multi-vibrator tube 94.

In thel de-energized position of relay 18,/as shown, the secondary winding of output tra-nsformer 88 is connected to ground on one -side through contact arm TB and to control winding H8 of erection motor 22 through contact arm 14, lead |20V and contact arm |22. One side of secondary winding of output transformer 9|) of amplifier' 84 is connected to ground and the other sdethereof is connected to control winding |24 of erection motor 26. through contact 88 and contact arm |26. Relay 18 is actuated by closing switch |28 Whichwill connect a source off electric power such as battery |38 of the control windingof the relay through a time delay device |32. The time delay device comprises a heater .element |34, in heat exchanging relationship'with iii-metallic strip |36, connected across the battery y|30 when switch |28 is closed. The bi-metallic strip is normally out of engagement with contact |38. When switch |28 is closed and heater |34 is connected across the battery, bi-metallic strip '|36 will be gradually heated and move toward contact |38. The time elapsed before strip |36 engages contact |38 depends on the particular design of the device and in the prsent illustration itt will be assumed that contact will be made -approximately 30 seconds after switch |28 has been closed. Actuation of relay 'I8 will cause contact arm |48 to engage contact |42 and close the third` phase of the three phase gyro motor indicated at |44 which will not operate unlessY energizedby all three phases of the A. C. supply. Actuation of relay 'IB-will also reverse the connection of secondary winding'oftransformer.8|l so that the side previously connected to ground will now be connected to' lead |28 and the side which previously was connected thereto will now -be connected to ground. Simultaneously contactlarm |22 will move against contact86 and thus connect the secondary winding of. transformer 9|! to control'winding ||8 'of erection motor-22 and contact arm |26 will move against contact |46 connected to lead |20 and thus'connect thereversed secondary winding vof transformer-831:0

65j control winding |24 of erection motor 26.

"nated turn.

' Leads |58 andy |52 from pick-oils 20'and"24fare connected to'the'i amplierof the automatic'pilot Y in the usual manner and Aarthe function ofthe automatic pilothasx no bearing..` on the Ypresent The main three-phase breaker |54 is shown as being mechanically coupled to switch |28 so that the switch is closed simultaneously with the breaker.

Coming now to the operation of the above# described device, it will be assumed that the gyroscope is at standstill and that the rotor axis is at some position other than true vertical and that it is desired to bring the rotor spin axis into vertical prior to the application of power to the gyroscope. The main breaker |54 'is closed whereby two of the windings of thegyro, the primary windings of pick-olf devices 20, 24, 28 and 30 and the constant phase winding of motors 22 and 26 will be energized. Switch |28 is closed simultaneously with breaker |54 whereby current begins to fiow through heater element I 34 of time delay device |32. As previously described, with the relay I8 in de-energized position the combined amplified output from pick-olf and pitch pendulum 32 is connected to control winding I I8 of erection motor 22 and the combined amplified output from pick-off 24 and bank pendulum 36 is connected to the control winding |24 of erection motor 26. In unaccelerated, straight, level flight, a signal proportional to the angle between the spin axis of the rotor and supporting member I2 about the pitch axis will be induced in the secondary winding 44 of pick-off device 20, and a signal proportional to theA angle between supporting member I2 and the vertical about this axis will be developed in the secondary winding 42 of pitch pendulum 28. These signals are combined algebraically and the resulting signal will cause erection motor 22 to rotate casing I0 about trunnions I4 until the combined signal across'the secondary windings 44 and 42 vof inductive devices 20 and 28 is zero at which time the rotor spin axis will be in a true vertical position in the pitch axis., Similar action will take place about the bank axis wherein erection motor 26 will cause rotation of gimbal ring I2 about trunnions I8 until the signal from pick-01T device 24 and bank pendulum 30 are equal and opposite at which time the pitch axis of the gyro defined by trunnions I4 vwill be in a true horizontal position. It is thus seen that the spin axis of the rotor will be brought to true vertical position regardless of the position of the mount and hence supporting member I6. Time delay device |32 is designed so as to delay the closing of relay 'I8 until complete erectionhas taken place at which time bi-metallic strip |36 has been heated to such an extent from heater element I 34 as to engage contact |38. This will energize relay 18 to close the thirdphase of g'o |44 through contact arm |40 and contact It is well known in the art that in order to precess a spinning rotor, torque must be applied 90 away from the direction in which it is desired to have the axis precess. Thus it will be seen from Iig. 1 'that in order to precess the spin axis in the transverse direction with respect to the d-irection of flight or in other words about trunnions I8 it will be necessary to apply the precessing torque from motor 22 and in order to precess the axis of rotation of the rotor in the direction of flight or about trunnions I4 it will be necessary to apply the-precessing torque to-motor 26. The reversal of the connections of motors 26 -and 22 is accomplished as above described by the yaction of relay I8 which transfers the output of the secondary winding Ofoutput transformer 90 .from'contact arm |26 and control winding |24 of switch 62 will again be closed.

erection motor 26, to contact arm |22 and control winding |I8 of erection motor 22. The relay simultaneously reverses the phase of the secondary winding of output transformer 80, disconnects it from control winding |I8 of erection m-otor 22 and connects it to control winding |24 of the erection motor 26 through contact |46 and contact arm |26. Thus as soon as the time delay device |32 actuates relay 18 the gyro is energized and the connections of erection motor 22. and erection motor 26 are interchanged. Because Aof the particular arrangement of the components illustrated in Fig. 1 it is necessary to reverse the output phase of the secondary of transformer 80 when switched from one motor to the other, but as this feature is of small importance it is not deemed necessary to analyze the reasons for thus reversing the phase.

The precession rate used to erect a vertical gyro is usually a compromise between several conicting factors. In order to obtain reliable erection even after considerable service of the gyroscope with consequent deterioration of the gimbal bearings, it is desirable to have a large erection torque. A large erection torque, however, will give the gyro a fast erection rate and thus cause :it to follow the dynamic vertical instead of integrating it. In order to integrate the vdynamic vertical the precession rate should preferably be Very slow. In accordance with the teachings of copending application Serial No. 102,671, filed July 1, 1949, and assigned to the same assignee as the present application, multi-vibrator 92 is provided to block the amplifiers of the pick-offs during certain predetermined periods whereby a.

large erection signal of low average value may be applied to the torque motors. As was previously explained the conventional multi-vibrator 92 will cause a pulse to appear across cathode resistor |06 in the form of a periodic square wave. It has been found preferable to adjust ganged capacitors I I0 and I I2 so that the positive pulse will be of a duration of approximately of the multivibrator cycle.

Amplifier tubes 58 and 66 are designed so asto operate normally with no voltage across resistor |06 or in other words with grid leak resistors I4 and I I6 c-onnected to ground potential. When a positive voltage pulse appears across resistor |06 grids 56 and 64 of tubes 58 and 66 are driven positive with the result that the tubes are saturated and no useable signal will be transmitted therethrough. Thus for the period the cathode of tube 84 is positive, the amplifiers will be made inoperative and no signal will be transmitted to the erection motors during this period. By varying the ganged capacitances IIU and II2 the period of inoperativeness of the amplifiers may be changed. In the present illustration the ganged capacitors were adiusted so as to cause the ampliers to be inoperative during 75% of the time.

When it is desired to make a coordinated turn of the craft manual control unit or handle |48 of the automatic pilot is turned either to the right or the left as the case may be and this will open switch 62 to disconnect erection motor 22 because when the craft is making a coordinated turn the pendulum 36 will no longer indicate true vertical but will follow the dynamic vertical. When the manual control unit' |48 is again returned to normal position for straight flight.

Although but one embodiment of ythe invention has been illustrated and described in detail, itfis to be expressly understood that the inventionis 7'v notlimitedthereto; Various changes; canzbe;y madefvin'the designand. arrangement of the parts'. without departingfrom the fispirit andxscopegof thefinventionras the same will now be funderstood; by-:thoseskilled in` the.A art.r

1.' Control means .for bringingthe spinaxis 1of a.three-degree-of:freedom gyrosc-ope .into .-anor-` mal-lylverticalposition from an inoperativeorrest position and for thereafter: maintaining thesspin; axis a normally 1 vertical iposition; comprising; torquamotors:associatedmi-thithe .banky and pitchy axes fofisaid "gyroscope, means,` responsive to Vdise placement `*ci saidspin 'axis zfrom said normallyvertical-vposition about said lbank andffpitch axis; and means forr connecting. said"v displacement, meansforoper-ating saidfbank and pitch .torque motorsfor bringing said spin-axis fromuanzinoperativeor rest positionlinto a .normally.=vertical position and Efor thereafter-reversing connection. offfsa-id displacement means with said capirand pitclhhtorque motors Ato Ymaintain saidk spin: axis in said'normally `vertical position.

2. Control means'fcr lbringing thespinaxis -of av-three-degree-of-freedom gyroscope into .a normallyYV lvertical position iromfan inoperative-or rest position and -for Vt: ereafter maintainingfthe spirr--a-xis ay normally vertical position, ,comprisingtorque `motors associated with a the vlianl; andfpitc'lffaxes'ofsaid "gyro, means responsive to' displacement `of saidA spin axis from 'saidA nor-- mally vrticaliposition about said-.bank and .pitch axes; pendulous-means associated with thezbank and 'pitch axes and responsivefto displacement of saidfspinv axis relative.. to :said 'bank andpitch axes;-andmeans for. connecting said v'pendulous means for operatingsaidbank and pitch torque motors for bringing said spin axiszfromfan inoperative-or rest position into a normally vertical position and for thereafter-reversing connection of=fsaid pendulous Vmeansl with said bank g and pitch torque motors tov maintain said` spin-axis in said normally vertical'position.

3. Control means for bringing the spinaxis of athree-degree-ofefreedom ygyroscope intoy anormally-fvertical position: from-an inoperative' orl rest position and for.' thereafter maintaining the spin axis in a normally vertical positioncomprising torque motors associated Withthefbankfa'nd pitclraxes of said gyro, pendulous means associated'with the bankandipitch axesand responsive displacement' of 'said' spinaxis Vfrom said normally verticabposition vabout said bank and pitch'.I axes, `means 4ior Aconnecting l'said Ypendulous mea-n'sforloperating said .banlrf and pitch torque motors for bringing vsaidspinaxis roman" inoperative or rest` position4` into a normally-ver tical positiomand time delay means'operative on thel Yexpiration of `Vav predetermined inter-valof time -ior reversing. connection of vsaid pendulor-s means-'with vsaid VbankV and' pitch torque motors to maintain said spin'axisinfsaid'normaily'verticalpositionz y 4l Control 'means for bringingfthef'spinfaxis of aythree-degree-of-freedorngyroscope-into a normally` vertical 'position from aninoperativeor rest :position and for' fthereaf ter maintaining r`the spineaxis in a; normally vvertical .positioncomprising torqueV motors associated 'with the3bank andpitch axes of saidgyro; pendulous :means.;as sociatedwith .thebank and pitch axes andresponsive to displacement of .saidf'spin axis from said normally'. vertical'. position abouti said t. bank and pitch. axes, means -forconnecting said-penduf lousrfmeans :for operating said; bankzand :pitch tcrquefmotors for. bringing.,saidffspin axis ffrom an inoperative or?` rest 'position'v into-1r 5 the rotorfof jafgyrdverticallinto alnor-mallyvers.

tical position fromv a,.,rest .position-vin which vthe rotor is stationary.. with its spin-axis in .a-posi-.f` tion other, than a a vertical position .and for/.tirere,-vv after..` spinning said ,rotor in maintaining..tries-pin` axisin a normally.verticalpositiom.comprisingfa r'sttorque A.motorfor, turningfthev rotor. about'. oneaoil its y.. axes Mofffsuspension, a second S- trque-Y motor for@turning-.thetrotorabout another .ofigits' axes ,.of.. suspension, means V.responsive to. relative displacement of the vrotor vspin axis .with :said-(one. axis ,.ofsuspensiou .connectedy for operatingsad iirstftorque motor, meansresponsive to relative displacement of the rotor; spin -v axis.withsaid othenaxis .of suspension connected for operating said second torque motor, saidresponsivemeans acting.. tooperate said motors. .wherebysaidfrotor spin. axis Vis brought intov anormally vertical .positio'n, and meansoperative aftersaid spinaxis is brought I to its .normally vertical positionf for,V spinningv said rotor and for `disconnecting said first responsive, means fromA saifirst .torque motorand yfoi-. connectingit with.. said-second torque. motor and fordisconnecting .said second responsive means rfrom said vsecondto'rque motor and `for connectingitto saidiirst torquemoton pick-.off-device associatedtwith an `axisof .saidgyroscope. for developing.v aasignal across ancute. put. thereof as ya Afunction of the deviation ofrsaid spin. axis from normal operating position vabout said `axis,V torqueA means Aassociated. with said axis.torque means. associated With1anfaxis ..of said vgyroscope perpendicular to said axis, .means including a time. delay. device for connecting said pick-oir." device4 and said torque means to.- a source ofenergizing power and .forfconnecting said .nist-mentioned torque means for-.operation in--response to signal across -saidfoutput4 ofsaid pickof. device for .bringing rthe I.spin .axisV toqopgerating position andafter a` predetermined-:time interval established by said Itime delaydevice for disconnectingv said rst-mentionedvtorque means and connecting said second-mentioned torque means tothey output, of saidpick-foii device Aand simultaneously, energizing. said gyro. v

7. Control means for bringing thepspin 'axis of al gyroscope 'tonormal j operatingposition. about a-scertain-V axis v'priorV to the energization of V"said gyroscope; l Y and'4 for; thereafter maintainingl the spinfaxisinnormal position comprising'a'l pick'- oif 'devicamounted for developinga; s ignalacross an output thereof fas arfunction-of the kamount said spina-xis iseo operatingpositionabout said axis, a 'torque' device-associatedj Withisaid axis,

torque devicev assoeiatedwwith an-A'axis'perpenfdicular-to sa-idf certa-inaxis; switchingA means Ain; cludinga timedelay-device fo'rvconnecting said outputl-'ogfsaid pick-ofi# device sto `said 'first-mentioned torque` deviceu and fory connectingf'said pick-credevioe andsaidtorquameans lizo-afsource of energizingwp ower to f'causefsaid frst-mentioned .1.normally;J vertical;- position; and 5 means; for :Isubse@tuent-ly;A

torque means to bring said spin axis to operative position about said certain axis. and after a predetermined time interval determined by said time delay device for disconnecting said output of said pick-01T device from said first-mentioned torque device and connecting it to the second-mentioned torque device and simultaneously energizing said 8. In a system for erecting the spin axis of the rotating element of a gyro during normal operation thereof comprising bank pick-off means and bank axis erection means operative in response to signals from said bank pick-off means, and pitch pick-off means and pitch erection means operative in response to signals from said pitch pick-off means, means for erecting the gyro spin axis to vertical prior to the energization of the gyro comprising switching means for interchanging response of said bank axis erection means and said pitch axis erection means so that the bank axis erection means is operative in response to signals from said pitch pick-01T means and said ypitch axis erection means is operative in response to signals from said bank pick-01T means, and means for automatically operating said switching means to connect said bank axis erection means and said pitch axis erection means for normal operation and simultaneouslyl energize said gyro after a predetermined time interval.

9. Control means for bringing the spin axis of the rotating element of a gyroscope to normal operating position prior to the energization of said gyroscope comprising an inductive pick-off device for developing across an output thereof a signal proportional to the amount the spin axis is off normal operating position in a certain axis with respect to a mount'I for the'rotating element, an inductive pick-01T device for developing across an output thereof a signal proportional to the amount the mount is off in said axis, means for combining said outputs, torque means for bringing said spin axis to operative position in said axis when the rotating element is at rest, said torque means being connected to the combined outputs and operative in response to the combined signals of said two inductive pick-01T devices, torque means associated with an axis transverse to said rst-mentioned axis, and switching means including time delay means for disconnecting said first-mentioned torque means from the combined outputs of said pick-off devices after a predetermined time interval and connecting said second-mentioned torque means to said combined outputs and simultaneously energizing said gyroscope.

10. In a gyro vertical erection system comprising pitch axis torque means for erecting the spin axis into a normally vertical position about the pitch axis operative in response to pitch axis' pick-offs during normal operation of the gyroscope, and bank axis torque means for erecting the spin axis about the bank axis into a normally vertical position operative in response to bank axis pick-offs, means including a time delay device for interchangng the connections of said pitch axis torque means and said bank axis torque means for bringing said spin axis to Vertical position when the gyro is at rest and after a time interval determined by said time delay device for connecting said torque means for normal operation and for energizing said gyro.A

11. In a system for erecting an operating gyro vertical in the bank and pitch axis having bank pick-01T means and bank erection means and pitch pick-off means and pitch erection means, means for bringing the gyro to normal operating position prior to the energization thereof including means for utilizing said bank erection means for erecting the gyroscope in the pitch axis and means for utilizing said pitch erection means for erecting said gyroscope in the bank axis.

l2. In a gyroscope having a spin axis movable about mutually perpendicular axes at an angle to said spin axis, means responsive to displacement of said spin axis from a predetermined attitude, torque means for moving said spin axis about said mutually perpendicular axes, and means for rendering said torque means responsive to said displacement means to move said spin axis about said mutually perpendicular axes from a rest position substantially to said predetermined attitude and then reversing response of said torque means to said displacement means.

RUDOLF R. SELIGER.

REFERENCES' CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number v Name Date 2,297,268 Von Manteuiel Sept. 29, 1942 2,429,605 Brannin Oct. 28, 1947 2,441,307 Alkan May 11, 1948 

